The use of plastics has become pervasive in present-day products of all types. The processes by which plastics are formed into or integrated as specific elements with the products have been carefully developed to generally maximize the volume of product output and performance characteristics of the resulting plastic products. Typically, the polymer process is used to form a complete individual product, such as a packaging structure (plastic bottle) or an individual element of a larger article (gear member for a low power drive train, or a filament of thermoplastic for combining into yarn or synthetic textiles).
The traditional and well-known plastic forming processes include, among others, injection molding, blow molding, and extrusion. Each of these forming processes has several related sub-processing techniques, and they all require the plastic starting material to be transformed into a molten state for the process to perform as desired. The molten thermoplastic stream is generated by masticating plastic pellets (and perhaps some regrind from the offal of previous molding processes) to work and heat the resulting mass to molten temperatures. At times, this molten requirement mandates the use of relatively complex equipment, and the processing parameters must be precisely controlled for successful processing. It was important to consider all manufacturing methods while creating the novel and unique non-textile fabric of the present embodiment. Non-textile fabric here means a generally flexible web made of individual interconnected elements, the web having many of the characteristics of textile fabric, but not depending on fibers or fiber related processes for these characteristics. Chain mail is one example of a non-textile fabric. It was initially speculated by the inventors of the present embodiment, in European Patent Application no. 00 976 729.4 entitled, “Direct Forming of Non-Textile Fabric Elements from Thermoplastic Pellets or the Like”, that because the use of these traditional plastic forming processes can sometimes result in certain variations within the material by the time the material has reached its final form (an element that acts as a building block of the non-textile fabric), it may be of some use to, in conjunction with utilizing a novel manufacturing method herein referred to as “direct forming”, utilize solid phase (cold) forming techniques. However, through experimentation, prototypical analysis, and finite element analysis methods, it has been determined that indeed, not only are solid phase forming techniques nonessential towards the production of the elements, but that the elements themselves and therefore the non-textile fabric in its entirety may be made by a variety of manufacturing methods. In fact, it has been shown that one method that yields very favorable results is injection molding.
The resultant material from the Direct Forming process, known as “Flexlock”™, represents an application of modern materials science and novel production techniques to the concept of chain mail. The physical construction of Flexlock comprises intimately interlinked hard, durable elements resulting in up to four bending axes and mimics the flexibility of ballistic fabric or leather. Unlike these conventional mediums, however, Flexlock panels can provide a wide range of physical strengths, depending on the base materials from which the interlocking elements are formed.
An advantage of Flexlock over fiber-based armoring or “ballistic” materials that lose strength upon becoming wet, is that Flexlock is inherently more moisture tolerant than conventional fiber based ballistic materials due to the vastly lower net surface area presented by the directly formed elements, and Flexlock will not wick moisture into the laminate, and can incorporate hydrophobic materials in the composition of its elements.
Also, the reception of projectiles in current fiber-based armor involves reliance on frictional fiber interaction to entangle and slow the projectile. The lubricating effects of moisture degrade this frictional fiber interaction. A benefit of incorporating Flexlock into a body armor system is that Flexlock elements do not rely on such frictional interaction, but are instead integrally and intimately coupled to one another to radially transmit high strain rate impact forces from a point of impact outwardly through the intimately interlocking, adjacent elements.
Another advantage of Flexlock over fiber-based systems is that unlike fiber, Flexlock elements are highly resistant to abrasion. Flexlock would therefore be of great value in areas contaminated with airborne or waterborne sand or dust. A further advantage of Flexlock is that it can be strategically designed to provide increased levels of protection in vulnerable areas of the protected person or item while providing a satisfactory level of protection in the less crucial regions. For example, a continuous panel of Flexlock can include areas of increased stiffness simply by increasing the stiffness, in particular the inherent frictional stiffness provided by the intimately formed connections of the individual elements in that area. For example, a higher degree of protection (stiffness, toughness, or other properties), may be desired over areas like organs, the head, neck, and shoulders, or sensitive portions of equipment, while still providing an appropriate level of protection over the remainder of the person or item. This feature lends economic benefits to the use and production of Flexlock. This can be achieved by resin fusing or by simply layering sheets of Flexlock material over crucial sites where high degrees of flexibility may not be of utmost importance.
The resulting Flexlock product has the desired qualities of flexibility, durability, mobility, strength, and sustainability that were predicted in the previous, aforementioned applications.
Of course it is still possible to manufacture the present embodiment by utilizing the theories and techniques of solid phase forming. Shell Development Company developed solid phase forming, or superplastic forming, and “Scrapless Forming of Plastic Articles” was created by Dow Chemical Company. This solid phase forming process is used to create monolithic plastic articles having high heat distortion temperatures, expanded or porous layers with integrally formed skin, using ultra high molecular weight polymers, and blended or layered structures of two or more materials. A related process is also used in the forming of metals, particularly aluminum or titanium, to form forged aluminum shapes from precisely formed slugs of metal.
It has been stated, within the abovementioned PCT applications, that the non-textile fabric (NTF) is made by employing the novel and unique process of “direct forming”. Direct forming is a process wherein at least a portion of a “second” element of the non-textile fabric is created by forming the at least portion of the second element against an existing “first” element or portion thereof. Simply, a portion of the first element forms a mold surface of the next, second element. In one such disclosed embodiment, the first and second elements comprised male and female elements. It should be understood by one of ordinary skill in the art that the NTF elements could take a number of varying geometries, be they in their entirety or in part “male” (protrusive) in nature, “female” (receptive), both male and female, or androgynous or neutral. The original disclosure's predicted success of creating a NTF by using the direct forming method is evident in the current, several promising NTF prototypes created by the inventors of the direct forming method and structure.
A benefit of the direct forming of some of the elements using injection molding methods in the manufacturing is that subsequent handling of the material and/or elements themselves is minimal. Again, it should be understood that as long as one used the direct forming method, (that is, forming at least a portion of one element by forming it against at least a portion of another element), the particular molding/shaping/forming/creating method used has been found to be of secondary importance. Thus only one manufacturing method is used in the creation of the NTF—both the elements and the NTF (assemblage of elements) is created by the same method and therefore it could be said in the same step. In one embodiment, the starting material is a polymer pellet. Of course, it should be understood by one of ordinary skill in the art that the starting material could be of any material composition including polymer, composite, ceramic, metal, liquid metal or metallic glass, organic, or any other material. Furthermore the state and/or shape, volume, properties and so on of the initial stock may vary—the stock could comprise liquid, solid, gas, powder, and so on.